在 Newtonsoft.Json 中处理十进制值

Handling decimal values in Newtonsoft.Json(在 Newtonsoft.Json 中处理十进制值)

问题描述

已经快 5 年了，我不认为这是要走的路.客户应以正确的数字格式发布数据.使用 React 或 Angular 等当前框架，或者使用适当的架构和错误处理和验证，我认为这几乎不是问题.

It's been almost 5 years and I don't think this is the way to go. The client should post the data in the correct numerical format. With current frameworks like React or Angular, or with a proper architecture and error handling & validation, i think this is almost a non-problem.

但是，如果有人想展示他们的 Json.NET 肌肉，请随时查看答案.

But if anyone wishes to flex their Json.NET muscles, feel free to check the answers.

我有一个 MVC 应用程序，我在其中处理了一些 JSON.这很简单.我的 ModelBinder 中有这段简单的代码:

I have a MVC application and I handle some JSON in it. That's simple. I have this simple piece of code in my ModelBinder:

return JsonConvert.DeserializeObject(jsonString, bindingContext.ModelType, new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore,
    MissingMemberHandling = MissingMemberHandling.Ignore,
    Formatting = Formatting.None,
    DateFormatHandling = DateFormatHandling.IsoDateFormat,
    FloatParseHandling = FloatParseHandling.Decimal
});

public class MyClass
{
    public decimal MyProp { get; set; }
}

"{"MyProp": 9888.77}"

"{"MyProp": "9.888,77" }"

JsonSerializer serializer = new JsonSerializer
{
    NullValueHandling = NullValueHandling.Ignore,
    MissingMemberHandling = MissingMemberHandling.Ignore,
    Formatting = Formatting.None,
    DateFormatHandling = DateFormatHandling.IsoDateFormat,
    FloatParseHandling = FloatParseHandling.Decimal,
};



return serializer.Deserialize(new DecimalReader(jsonStr), bindingContext.ModelType);

public class DecimalReader : JsonTextReader
{
    public DecimalReader(string s)
        : base(new StringReader(s))
    {
    }

    public override decimal? ReadAsDecimal()
    {
        try
        {
            return base.ReadAsDecimal();
        }
        catch (Exception)
        {
            if (this.TokenType == JsonToken.String)
            {
                decimal value = 0;

                bool convertible = Decimal.TryParse(this.Value.ToString(), out value);

                if (convertible)
                {
                    return new Nullable<decimal>(value);
                }
                else { throw; }
            }
            else
            {
                throw;
            }
        }
    }
}

您可以使用像这样的自定义 JsonConverter 类处理这两种格式(JSON 数字表示和屏蔽字符串格式).p>

You can handle both formats (the JSON number representation and the masked string format) using a custom JsonConverter class like this.

class DecimalConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return (objectType == typeof(decimal) || objectType == typeof(decimal?));
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        JToken token = JToken.Load(reader);
        if (token.Type == JTokenType.Float || token.Type == JTokenType.Integer)
        {
            return token.ToObject<decimal>();
        }
        if (token.Type == JTokenType.String)
        {
            // customize this to suit your needs
            return Decimal.Parse(token.ToString(), 
                   System.Globalization.CultureInfo.GetCultureInfo("es-ES"));
        }
        if (token.Type == JTokenType.Null && objectType == typeof(decimal?))
        {
            return null;
        }
        throw new JsonSerializationException("Unexpected token type: " + 
                                              token.Type.ToString());
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }
}

要将其插入您的活页夹，只需将转换器的一个实例添加到 JsonSerializerSettings 对象的 Converters 列表中:

To plug this into your binder, just add an instance of the converter to the Converters list in the JsonSerializerSettings object:

JsonSerializerSettings settings = new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore,
    MissingMemberHandling = MissingMemberHandling.Ignore,
    Formatting = Formatting.None,
    DateFormatHandling = DateFormatHandling.IsoDateFormat,
    Converters = new List<JsonConverter> { new DecimalConverter() }
};

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